4.2 Factors Affecting Enzyme Activity Flashcards
What 4 factors affect enzyme activity?
Temperature, pH, substrate and enzyme concentration.
What must happen for an enzyme to catalyse a reaction?
The enzyme must come into contact with the substrate, and the enzyme must be the right shape for the substrate.
Describe how temperature affects the rate of reaction of an enzyme.
As temperature increases, ROR increases.
Explain how temperature affects the rate of reaction of an enzyme/
-Increasing the temperature of a reaction environment increases the kinetic energy of the particles.
-As temperature increases, the particles move faster and collide more frequently,
-So there are more frequent successful collisions between the substrate and the enzyme.
-Therefore, the rate of reaction increases.
What is the temperature co-efficient?
Q10, it is a measure of how much the rate of reaction increases with a10 degree rise in temperature.
How do you calculate the temperature co-efficient?
Rate at 10°C higher temp / Rate at 10°C lower temperature
Why are enzymes affected by temperature?
Because they are proteins.
Describe what happens to the bonds holding the enzyme together as temperature changes.
-At higher temperatures, the bonds holding the proteins together vibrate more.
-As temperature increases, the vibrations increase until the bonds strain and break, resulting in a change in the tertiary structure of the protein (i.e. denaturing)
What happens when the enzyme denatures?
The active site changes shape, and can no longer bind to the substrate, meaning that the enzyme will no longer function.
What is an optimum temperature?
The temperature at which enzymes have the highest rate of activity.
What happens to the ROR once enzymes have denatured?
The rate of reaction decreases rapidly.
How are the enzymes in organisms living in extremely cold environments adapted?
By having more flexible structures, particularly at the active site, making them less stable than enzymes that work at higher temperatures
How are the enzymes in organisms living in extremely hot environments adapted?
By being particularly stable. They have an increased number of bonds (particularly hydrogen bonds and sulfide bridges) in their tertiary structure. This makes them more resistant to temperature rises.
Why are enzymes affected by changes in pH?
Because enzymes are proteins, and the pH disrupts the hydrogen bonds in its tertiary structure.
What gives amino acids their specific shape?
The hydrogen bonds and ionic bonds between amino acid R-groups.
